Drilling bit



George J5. Larbqcic 2 Sheets-Sheet l Filed Feb, ll, 1924 G. B..LOUDERBACK Ma/wey.

,1m 1s, 19125.r

Jan, i3, 1925.

G. a. .-LQUDERBACK DRILLING BIT Filed Feb. ll, 1924 Patented Jan. 13,V1925.

GEORGE B. LOUDERBACK, OF.C`0MPTON, CALIFORNIA.

DRILJTNG Brr.

Application led February 11 1924. Serial No.-691,998.

To all whom t maj] concern:

Be it known that I, Geenen B. LoenennACK, a citizen of the United-vStates, residing at Compton, in* the county of Los Angeles and' State ofCalifornia, have invented a new and useful Drilling Bit, of which aspecification is set forth below.

In this specification, and the accompanying drawing, I shall describeand show a preferred form of my invention, and specifically mentioncertain of its more important' objects. I do not limit myself to theforms disclosed, since various changes and adaptations may b e madetherein without departing from the essence of my invent-ion as hereinafter claimed; and objects and advantages, other than thosespecifically mentioned, are included within its scope.

My invention relates to well .drilling bits for usev with rotary rigs.Its principal objects include; first, to provide a tool ot thischaracter having extensible cutting blades adapted'for beingperiodically advanced as they become worn, without removing the bit fromthe drill hole; second, to afford facilities for advancingthe cuttingblades, while unde'y ground, .in such a manner that the gauge of. thedrill hole may constantly be maintained. or even enlarged; and, third,to accomplish the above objects by means of a relatively simpleconstruction that may be depended upon to function as intended.

'lhese objects are accomplished by means ot the construction illustratedin the accompanying drawings, in 'which-- Figure 1 is alongitudinalaxial section of the upper portion of the tool in elevation;

Figure 2 is a similar section of the lower portion of the tool, taken onthe same plane as Fig. 1;'

- Figure B'is a longitudinal axial section of the upper portion of thetool taken on a plane revolved 90 degrees from that of the first twofigures;

y Figure 4 is a similar section of the-lower portion of the tool. takenon the same planeas Fig. El;

Figure 5 is a much enlarged perspective view of an upper portion of theoperating mechanism);

Figure 6 is an enlarged axial section of l. the lower portion of theoperating mechanism, taken on' the same plane as Fig. 3, an

Figures 7, 8, 9, and 10 respectiuelysaie 55 cross sections taken on thelines T--'T 8-8, 9 9, and lO-lO of Figs. 1 and 2'.

Similar reference numerals refer to siinilar parts throughout theseveral views.

In a general way my improved tool `is 60 adaptedA to operate in themanner of the ordinary fish-tail bit employed in rotary drilling, therebeing a pair of cuttingblade'lsn 1n substantially the same plane,extending oppositely from the axis. 1 The leading bot- B6 .tom edges ofthese blades do the cutting. In all such tools the Wear on the cuttingedgestends to become greater as the distance from the axis increases,due to the greater cutting speed and the greater amount of ma- 'I0terial encountered. In addition to this the tips have the additionalduty of maintaining the gauge of the drill hole and have to withstandthe abrasion caused by the unavoidable wobbling of the tool. Inconsequence of this the tips of ordinary bits soon become rounded andblunt, and the tool is thereby rendered unfit for further servico untilit has been withdrawn from the drill hole and redresscd. A so Obviously,in the case of deep wellsparticularly, the time lost in the repeatedfwith drawals and re-placement of ordinary. bits is often a matter ofgrave concern. Moreover, as the tips oi the cutting edges of such bitsbecome rounded by Wear, the drill Ahole loses its gauge and becomessmaller. Consequently, when a redress'ed tool of standard gauge issubstituted,it' has to perform a reamin'g operation before the bottom ofthe 90 hole is reached. This roaming duty comes entirely upon the tipsof the blades and in a large measure destroys their cutting elliciencybefore .the depth drilling` can be resumed.

In a previous application-for patent, filed January 16, 1924, Serial#686,569, I disclosed a novel type and arrangement of cutting blades,and means for a vancing them from the lovier end o'f the tool obliquelyto l0 the axis. Entirely vsimilar blades and' blade arrangement areemployed in the tool to be described, but are not claimed herein per sc.

The means employed for advancing the blades in the present case are,however, quite distinctive and constitute the present invention.

The adjustable cutting blades 11 and l2 are bifurcated and provided witha flange 13 on their leading faces at each side of their bifurcations. Athicker {lange 14 is provided at the leading side of their outer edges.lt now possible to make these ftanges, as wc'll as the whole leadingfaces ot' the blades, -very hard in comparison to the main body ofmetal. The cutting edges therefore ha've a greater' wearresistingquality and, tor that. reason, the blades have a marked self-sharpeningtendency. This tendency is further enhanced by the fact that the bladesare relatively very thin. but strength is not sacriiced since they arebacked up and supported,

close to their cutting edges, by the heavy metal of the tool body. Thelocalized thickening of the blades by the flanges'. where the greatesttendency to wear occurs. `tends to make the wear on the cuttingr edgesmore uniform and thus to prolong their effective drilling life.

Thisability to advance the cutting blades obliquely to the axis,provided .the Acutting edges have not been destroyed. makes the toolvery largely independent of the shape to which 'the blades may wear.Thus. in the event that tlre points of thel blades become rounded, thegauge of the drill holecan be maintained by advancing the blades, andthc tool will continue to cut asetectively as it. did before therounding occurred.

It will occur to some that', as the blades are obliquely advanced fromthe end of the tool, the cutting edges will recede from the center; andthat, in the form depicted. there are in fact no cutting edges at thecenter of the tool. It isr conceivable that in cert-aiu -formations,with a perfectly centered rcvolving tool, this disposition of thecutting edges might tend to leave a central core that `would interferewith the drilling. ln practice, however, this never occurs. The toolnever revolves truly about a fixed axis, and the unavoidable wobblingvprevents the formation of such a core, since -it would be quickly cutinto and destroyed if it occurred. Furthermore, the weight of the toolstring, which Ais'very heavy, could not be supported by a core'of thiskind. lt. would quickly' crumble under such a load. For those reasons notrouble. from cores is ever experienced in drilling operations of -thischaracter.

The body of my bit is made in semi-cylim drical halves 15'and 16. ofidentical shape. with accurately machined or ground faces.l These arecast or forged with variousl refcesses'such as 17, for theaccommodationof the working parts they are to enclose, and

are assembled face to face my means of ar threaded ring 18 at the top,and a wedge band 19 at the lower end.' The lower portion of thebody 'isslightly wedge-shaped, as indicated in Fig. 4, and isa modified ellipsein section, as shown in Fig. 10. This portion becomes increasingly elonated in cross section towards the lower en of the tool. W'edge band 19is driven from the bottom on to a slightly tapered seat against ashoulder at 20. Bolts 21, passing through thc bifurcations of thecutting blades, af-

ford still further security against displace-Y nient o f the bodyhalves.

The central portion of the tool body is' threaded at22 and a tubularhousing 23 is screwed upon it at that point. This housing is somewhatenlarged at its upper end and a tubular member 24 is screwed into thetop. Member 24 carrieslan integral taper-threaded pin 25 at its upperextremity, forengagement by the tool joints of -the tool string.`

The mechanism by which the cutting blades are held and controlled ismostly enclosed within housing 23 and the halves of the .tool body. Itcomprises a relatively long feed screw 26 engaged by a cylindricalflanged nut 27. The screw itself does not turn. It is lowered by turningits feed nut, which may be revolved but is longitudinall positioned bymeans of its flanges 28 whicv engage corresponding grooves in the bodyparts.

At the lower end of the feed screw is a flattened blade retainer 29having a, transversegroove 30 across each of its faces adjacent to thebttom edge. The two cutting blades are similarly grooved to form flangesattheir top ends, the end flanges of the -blades being adapted to fitinto the grooves of the retainer and vice versa. The cuttingl at alltimes by mea-ns of oblique grooves inY the body in which liangcs13 and14 of the blades are slidingly engaged. This isclelar yly illustrated inFig. 10 and indicatedby `dotted lines in Fig. 2.

As the blades are fed obliquely l l t) lil() Feed nut 27 is turned tolower the feed l,

screw by means of a ratchet clutch device."

This comprises an operating spool.].with

. comprise a pair .friction rollers ,power blocks 42 which are adaptedto slide 'radially in and -quill and to 1. -through the key end of thequill is smooth-bored to permit vthe operating screw it.- and isprovided a smooth bore, through which the feed screw passes. Theadjacent end faces of the feed uut and operating spool have radialratchet teeth 32, i lapted for mutual engagement.

Operating spool Ill has a multiple thread 33 on. its outer surfaceadapted to engage a toothed nut l-L. Beneath this nut isv a lighthelical spring supported at the bottom by a ball thrust bearing-36L Theupper portion of the operating spool is provided with a longitudinalkey-'way 3T A and 1s surrounded by the tubular end of the- 'lhis quillhas an internal 2li), engaging key-way 3.7 1n the operating spool, and

the latter' is adapted to slide longitudinally within the be rotated byit in any position, and key-way. The upper driving quill 38.longitudinal key to pass freely through with peripheral teeth 40 wherebyit may be driven.

In order to operate the feed mechanism just described friction drivedevices are located in the upper end of housing 23. These 'of'dirmetrically opposed 41 rotatably mounted in out of rectangularorifices cut for that purpose in the enlarged upper end of housing 23.The power blocks 'are normally separated. by compression springs 43, soas to re-act against each other and to force their respective frictionrollers into contact with the internal walls of the well casing.Revolving 'the tool will then cause the rollers to revolve` about theirindividual axes and furnish a source of power for operating the feedmechanism.

Reduction gearing, indicated at 44- is located Within each of the powerblocks and the power taken from th`e rollers is communicated to driveshafts'45 through `telescopic joints 46 and universal couplings 4T. Atthe lower endsv'of, drive shafts 45 are pinions 48 meshing 'with teethttl-of the driving quill.

lontrol of the feeding mechanism is accomplished through' an offsetplunger rod 49 at each side ot. the cutting blades. These are adaptedtoslide longitudinally in slots in the. tool body, and extend from thebot# tom of the tool nearly to its top. -Attheir upper ends the plungerrods are connected b v a yoke bar 50 and they are normally presseddownward and outward from the end of the tool. by a compression spring5l rc-acting against this yoke,4 At their lower ends the plunger rodsare fixed to an operating Shoe 52.

42 are provided with upwardly pointing wedge shaped grooves 53 inpeachof their lateral faces. Corresponding wedge shaped flanges 54areprovided lin a pair of sliding cams 55 fixed at the Power blocksproper points to the respective' plunger rods. F langes 54. are adaptedto engage grooves 53 to force the power blocks together' When the ramsare raised by the plunger rods. ln this manner. when the weight of thetool is allowed to rest upon shoe 52, the plunger rods and rams arcpushed upward and bring the power blocks together. Conversely when theweight of the tool is taken off shoe 52 the rods and cams are pusheddownward by spring 5l and the power blocks are forced outward by springs43 untilthe friction rollers are in contact with the well casing.Rotating the tool in this position will then operate the feed mechanismto advance the cutting blades from its lower end.

I have provided in my improved bit a means whereby number of turns mayfeed nut in the manner ]ust eration ot the feet described. Op-

a definitely pre-determinedbe imparted to the -driving 'mechanism beyondthis point will cause ratchet teeth`32 mechanism has already beendescribed in part. l'ts operation is as follows: On plunger rods 49 aresplines to engage the teeth of nut 34 to prevent its being turned.- Thisengagement takes place as soon as the weight of the tool is taken otfthe operating shoe a'nd the plunger rods are pressed downward by spring'51. The feeding mechanism =is then in position to operate as soon aspoweris applied to it. and operating spool is turned to lower the -feedscrew an nut. 34 is forced down Ward by the action llVhen nut 34 hastraveled downward as far .as it can goby reason of its reaching stops57, the further rotationof the operating spool will result in raisingthe latter and causing ratchet teeth. 32 to .become rl`isengagefl'."Tlietoothed nut. is restored 'to iis normal position b v reversing-thcrota-A tion of the tool while in its raised/[iosition.A Beneath feed nut'27 it is desirableto install a ball thrust bearingvl to reduce thefrictional resistance of this nut when it is being turned. At that timethe weight of the cutting blades is hung upon thefeed screw and issupported by this thrust bearing.

An important feature of my device remaining to be described is themanner in which circulating water is delivered in advance of the cuttingedges of the blades. `Within the upper portions of the body halvescirculating water grooves are pro# vided and are closed to form tightWater courses when the halves are assembled. A pair of smaller holes 59are the bottom "of each half to communicate with the respective lowerends of these Water courses. lhese small holes 59 are located ofmultiple thread 33.v

drilled from 10, just forward 56 adapted of the cutting edges of theblades, and in a position to deliver the circulating' water mostadvantageously.

W'hen the body halves are assembled, pipes (30 are brazed, or otherwisetightly jointed, into the upper ends of the water circulating groovesinthe body parts', anda distributing box Gl. is mounted upon the upperends of these pipes in the manner indica-ted in Figs. l and 3. vThis boxhas a central inletpip'e 62 adapted` to pass through an axial bore inpin 25, and be made tight therein by a stuffing box such as isindicat'ed 1n Fig. 3 at 63.

The construction and operation of the es'- sential elements of myinvention `will be clearly understood from the foregoing description anddrawings. Reaming lades Getmav be employed in the manner indicated ifthought dcsirable,but ordinarily these will not he required, or willhave very little duty to perform, on account of the ease with which thegauge ot the drill hole may be maintained by advancing thc cuttingblades.- i

I wish to call particular attention to the fact that, although thecirculating water passes through my device from end to end,

it is contained in a tightly closed course y throughout, and is nowherepermitted to come into contact with myn-of the working parts. The powerblocks may be`\packe by felt strips where they move into and out of thetubular housing, and the latter may be packed with heavy grease as afurther insurance of keeping out` mud and water. The more delicate ofthe working parts are tightly enclosed in the power blocks and bodyhalves respectively, and may be constantly immersed in heavy oil orgrease introduced through suitable plug holes for that purpose.

I claim as my invention:

l. A. drilling bit having cutting blades adapted tor being advancedobliquely to its axis and means adapted for actuation by frictionalengagement with the walls of a drill hole for making said advancement.

2. A drilling bit having cutting blades adapted for being advancedobliquely to its axis and means comprising a feed nut for making saidadvancement; said means being operative through frictional engagementwith the walls of a drill hole.

3. A drilling bit having cutting blades adapted for being advancedobliquely-to its axis and means comprising a non-rotatable feed screwwith a rotatable thereon for making said advancemergaf'said means beingoperative throu h.-iction:1l engagement with the wallsfo a drill hole.

f'f drilling bit having cutting blades adapted for being advancedobliquely to its axis and means comprising a non-rotatable feed screwwith a rotatable nut thereon for maki said Iadvancement.; said meansbeing operative through frictional engagement with the walls of a drillhole and controlled by plunger rods normally projecting from the end otsaid bit.

A drilling bit having cutting blades adapted for being advancedobliquely to its axis'and 'means comprising a rotatable feed nut formaking. said advancement; said means being operative through `irictionalengagement with the walls of a drill hole and adapted for automaticdisengagement from said nut when the latter has made a pre-determinednumber of revolutions.

6. A drilling hit having cutting blades adapted for being advancedobliquelyto its axis and means comprising a rotatable feed means-beingoperative through trictional engagement. with the walls o'E-)a drillhole and adapted for automatic disengagement from said nut when thelatter has made a pre-.determined number of revolutions; said hit havingslidahle plunger rods normally projecting from its end whereby saidmeans can be controlled.

7. In combination with a drilling bit having cuttingblades Lidapted foradvancement obliquely to its axis; 1a rotatable feed nut adapted forcausing said advancement; an disengageable means operative through fricdtional engagement with the walls ofa drill hole for rotating said nut. i

8. In combination with a drilling bit having cutting blades adapted foradvancement obliquely to its axis: a rotatable feed nut adapted forcausing said advancement; and disengageable means operative throughfrictional engagement with the walls ot a drill =hole for rotating said.nut a pre-determine number of revolutions.

9. 'In combination with a drilling bit having cutting blades adapted foradvancement ohliquely to its axis; a rotatable fred nut adapted forcausing said advancement: and means operative through frictioual'engagement with the walls of a drill hole for rotating said nut andautomatically disengaging' therefrom when said nut hits-made apredetermined number (Ltrevlutions.

10. In combipatlf'n with a drilling hit having cutting blades adaptedfor advancementfo'liquelv to its axis: a rotatable feed :mit adapted forcausing said advancement; and means for rotating said nut apre-determined number vot revolutions comprising driving rolls adaptedfor rictional engagement with the walls ot a drill hole disengageablyconnected with said nut.

11. In combination with a drilling bit having cutting blades adapted foradvancement obliquely to its axis; a rotatable' fcc( nut adapted forcausing said advancement diametrically opposed power blocks adapte( formutual reaction through interposed com ,naomi pres-sion Springs andhaving rollers' aflantecl for frictional engagement with the vwal of a(li'ill hole; and flexible means for delivering power from Said rollersto said nut.

l2. In combination Willa a drillingl bi having cutting blades adaptedfoi` advanceinem obliquely to its axis: a rotatable 'leed nut adaptedfor causing; said advancement; dialneirically opposed power blockshaving 10 interposed compression springs anfl rollers aflaated 'foriictional ongpgomen will 'rle wal s of a glrill hole; and flexible meansfor delivering power 'from saiil rollers to said nut; said means beingrautomatically dise gageable from said nut when the latine;r has made apreefletei'lninefl nmnnei olE revolu- ,f/ions and adapt'erl loi' lmnp;controlled by plunger rods normally projecting 'from the end of saidbil'.

GEORGE B. L() UDERBACK.

